Fibrate-related compounds area class of compounds sharing a .alpha.-methyl-propionic acid locus as part of the overall fibrate structure. Fibrate-related compounds are known as lipid and/or cholesterol reducing agents and include, for example, gemfibrozil (Lopid, commercially available from Parke-Davis, U.S. Pat. Nos. 3,674,836 and 4,126,627), nafenopin, which has been studied by Ciba-Geigy for similar uses, and ciprofibrate (Ciprol or Lipanor available from Sterling, Winthrop, Inc., U.S. Pat. No. 3,948,973). The structures of these compounds are provided below: ##STR1##
The compound ciprofibrate (.alpha.-2-methyl propionic acid) is currently being developed as a lipid reducing agent by Sterling Winthrop, Inc. The compound is produced as a (.+-.)-racemate. It is known that the active enantiomer is the R(+) acid. Because the compound is a racemic mixture, commercial scale-up yields for the desired R(+)-enantiomer are low, additionally, the inactive S(-) compound may be associated with unwanted side effects. Therefore, it would be desirable to have a cost-effective high yield process for the selective production of one or more of the enantiomers as compared to the racemic mixture currently produced. There is a need for an enzymatic resolution process to selectively produce either the S(-) or the R(+) enantiomer of the free acid.